The objective of the proposed research is to delineate the GnRH self-priming pathway and its intersection with progesterone receptor PR. The specific aims are: 10 to determine steady state levels of PR mRNA and levels of PR-a and PR-b isoforms and their regulation by estrogen in gonadotropes and a newly developed cell line, LBT2 cells; 2) to test whether the temporal pattern of PKA and PKC activities interact to influence PR mediated self-priming; 3) to test the hypothesis that PKA is a mediator of self priming, using a single cell model in which membrane capacitance and intracellular Ca are measured as indices of exocytosis and secretion; and 4) to use microinjection of PR antibodies or antisense oligonucleotides into single cells to test the hypothesis that PKA and PKC interact at the level of PR to induce self priming.